Bulky yarns



sept. 1o, 1968 -rol/[suino oHFu KA z-:TAL 3,400,531

BULKY YARNs Filed Jan. 6, 1967 United states Paiemo 3,400,531 y BULKY YARNS i Toshio Ohfuka, Hiroshi Yokoyama, Hideo Sato, and Yoshikazu Inai, Funi-shi, Japan, assignors tvo Asahi Kasei Kogyo Kabushki Kaisha, Osaka, Japan, a corporation of Japan l Filed Jan. 6, 1967, Ser. No. 607,758

4 Claims. (Cl. 57-140) ABSTRACT F THE DISCLOSURE Bulky yarns excellent in Vshape stability, compression elastic modulus, surface smoothness, flexibility,y luster, bulkiness and feeling of fullness are prepared by the steps where acrylic non-shrinkable fibers, shrinkable fibers of limited shrinkage and acrylic conjugated fibers of limited shrinkage and latent crimping ability are vmixed in a specific range 0f mixing ratio and then the mixture is spun by mixed-yarn spinning process or twisted by mixed yarn twisting process.

The shrinkage degrees of the component fibers are respectively, between 0 and 4, between 5 and 35, and between 0 and 8. The latent crimping ratio referred to above is between l0 and 35. The mixing ratios (weight percent) are, respectively, more than more than 25% and between 50% and 10%.

DISCLOSURE The present invention relates to improved acrylic bulky yarns consisting of three kinds of component fibers which are different in characteristics and composition from each other. Furthermore in detail, it relates to excellent acrylic bulky yarns prepared by subjecting non-shrinkable fiber, shrinkable fiber of limited shrinkage and acrylic conjugated fiber of limited shrinkage and latent crimping ability, which are respectively limited in a specific range of shrinkage, latent crimping rate and composition ratio, to mixed yarn spinning or mixed yarn twisting in a specific range of mixing ratio.

Acrylic bulky yarns have so far been prepared by mixed yarn spinning of non-shrinkable fiber and strong shrinkable fiber. Further, there has recently been developed the production of acrylic bulky yarns, characterized by preparing the so-called conjugated fibers having the cross-section of two or more bonded components which are different in thermal shrinkage and swelling specificity from each other. TheV formerhas such drawbacks as poor feeling of fullness in bulkiness and low elastic recovery after compression. The latter has been developed for improving the above drawbacks. It has, however, come to be recognized that the said bulky yarns of conjugated bers are excellent inelongation, elastic recovery and feeling of fullness, but are low in shape stability, are of rough surface touch and weak luster as the products due to fine natural crimps of their component fibers, and wholly tend to lose the special soft touch of acrylic yarn products.

The object of the present invention is to provide acrylic bulky yarns which have no drawbacks of the conventional bulky yarns, and are of smooth and soft surface touch, excellent luster, high compression elasticity, large elastic elongation, full and abundant bulkiness and excellent shape stability.

Another object of the present invention is to provide bulky yarns, prepared by carrying out the mixed yarn spinning or mixed yarn twisting of non-shrinkable fiber of limited shrinkage, and acrylic conjugated fiber of limited shrinkage and latent crimping ability in a specific range of their mixing ratio.

3,400,531 Patented Sept. 10, 1968 The other object of the present invention isfto provide improved bulky yarns prepared from three kinds of said component fibers which are respectively limited in a specific range of shrinkage, latent crimping rate and composition ratio (weight percent).

The further object of the present invention is to progade a novel structure of three kinds of said component ers.

Other objects and merits of the present invention may be made clear in the following explanation.

Bulky yarns according to the present invention consist of acrylic non-shrinkable fibers (abbreviated to Nbers, hereinafter) consisting of a single component containing at least more than 50 weight percent of acrylonitrilecomponent, shrinkable fibers (abbreviated to S fibers, hereinafter) and acrylic conjugated fibers (abbreviated to C fiber, hereinafter) characterized by the cross-section containingat least more than 50 weight 'percent of acrylonitrile in the average composition and having the essentially bonded structure of two or more different components.

l In a case that the shrinkage a and latent crimping ability v of three kinds of said component fibers respectively satisfy the following conditions;

C are in the limited range according to the following Equations 1 to 4:

N+S+C (1) N215 (2) C225 (3) 50%/,R10 (4) it has been found that the obtained bulky yarns are excellent in shape stability, compression elastic modulus, surface smoothness, flexibility, luster, bulkiness and feeling of fullness, where r and 11 are defined by,

11 X100 (Percent) 1,-13 v 12 (Percent) where l1 is the length of fiber under loading of 0.2 g./ denier before the heat treatment, 12 is the length of fiber under loading of 0.2 g./denier after the heat treatment, and 13 is the length of fiber under loading of 0.01 g./ denier after the heat treatment.

As the sample, about l m. of about thirty thousand denier tow is used. As for the heat treatment, three folds of said sample are softly wrapped in gauze and are placed in a wire netting basket and, after the basket is submerged in 100 C. hot water and are left as it is for l0 minutes, the temperature is lowered to 30 C. by pouring water, and the sample is taken out and is subjected to centrifugal dehydration and hot wind drying at 70 C.

The values of u and v are rather largely varied depending upon the position of sampling, and therefore the number of repetition for sampling and measurement is preferably more than 20.

As may be clearly understood from the said definition, a represents the shrinkage of fiber length along its fibrous axis before and after the heat treatment, and v is a parameter representing the degree of crimping for crimps formed due to the heat treatment of latent crimp fibers.

By the bulking process, bulky yarns according to the present invention are provided with peculiar structure which has not been observed in the conventional yarns.

Further, bulky yarns according to the present invention have the peculiar structure, which makes a contribution to the display of said characteristics. The structure of bulky yarns according to the present invention may furthermore clearly be understood by the annexed drawings and their related explanation.

FIG. l is a brief side view of bulky yarns according to the present invention and FIG. 2 is a brief cross-sectional view of bulky yarns according to the present invention in the state of twin yarn.

In FIG. l, N represents the position and state of nonshrinkable fibers after the bulking treatment, C represents the position and state of acrylic conjugated fibers of limited shrinkage and latent crimping ability after the bulking treatment, and S represents the position and state of shrinkable fibers of limited shrinkage after the bulking treatment. The shrinkable fibers are positioned in the central portion of bulky yarn in the state of being relatively elongated and are surrounded by the conjugated fibers,

which produce bulky crimps depending upon the difference in shrinkage from the shrinkable fibers and the degree of crimping, and by the non-shrinkable fibers of no or small crimps. The conjugated fibers which produce crimps come t be positioned inside the non-shrinkable fiber, as the conjugated fibers produce crimps. Thus, the surface of the yarn is mainly covered with the non-shrinkable fibers.

Similarly, FIG. 2 illustrates the bulky state in the case of twin yarns. In this figure, two hatched circles represent two single filaments and a large circle surrounding them represents the whole body of the bulky yarn. In the two single filaments, A represents the surface layer portion, B' represents the intermediate layer portion and C represents the central portion (the core portion), while A represents the surface layer portion, B represents the intermediate layer portion and C represents the central portion (the core portion) in the whole body of the bulky yarn.

Not only in the single filament but also in the whole body of the bulky yarn, the relative presence of the nonshrinkable fibers is the highest in the surface layer portion, the most of the shrinkable fibers are present in the core portion and the most of the crimped conjugated fibers are present in the intermediate layer portion.

The several kinds of said excellent properties of the bulky yarn according to the present invention are resulted from such the peculiar structure as shown in FIGS. l and 2. That is, it is of very smooth and soft surface touch, the so-called acrylic touch, and much improved luster as compared with bulky yarns of acrylic conjugated fibers, probably because the surface of the bulky yarns according to the present invention consists mainly af acrylic bers of smooth surface. It is of much improved shape stability as compared with bulky yarns of acrylic conjugated fibers, probably because the conjugated fiber portion which is elongated by slight external tension is protected from the external force by the shrinkable fibers which are shrinked and are mostly distributed in the neighborhood of the core portion. Further, excellent cornpression elastic modulus and feeling of fullness of the bulky yarns according to the present invention are resulted from the conjugated fibers which are most distributed in the intermediate layer portion.

Thus, in the bulky yarns according to the present invention, three components of acrylic nonshrinkable fibers, shrinkable fibers and acrylic conjugated fibers form the peculiar structure system and, due to their mutual perfection, form the bulky yarn of entirely different and improved properties from those of yarns consisting of one kind of the fibers.

As the acrylic non-shrinkable fibers N according to the present invention, the single component fibers of wellknown acrylic polymers containing at least more than 80 weight percent of acrylonitrile are the most suitable from the viewpoint of touch, feeling, brightness of color tone after dyeing, thermal properties and the like. However,

the acrylicA fibers containing at least more than about 50 weight percent of acrylonitrile are sufficient for achieving the object of the present invention. The shrinkage 1N of N fibers is required to be less than about 4%. As N fibers are preferably distributed as much as possible in the surface of bulky yarns according to the present invention, it is desirable that the entangle ability of N fibers is smaller. Further, favorable results are obtained by increasing the roundness of the fiber cross-section. From this point of view, suitable acrylic fibers are obtained by wet spinning especially from an inorganic solvent such as a nitric acid solvent.

Next, the shrinkage fr, of the shrinkable fibers S constituting the bulky yarns according to the present invention is required to be in the range of 5 to 35%. If it is less than 5%, the bulkiness of the woven products is rather insufficient and the improvement of shape stability can hardly be expected. Or, if it is more than 35%, the bulkiness is too large and thereby the beautiful appearance of the products is lost.

It is especially suitable that S fibers are acrylic fibers. However, also suitable are the well known shrinkable fibers of polyamides, polyvinyl chloride, polyvinylidene chlorides, polyester, polyethylenes, vinylones, polyvinylidene cyanides, and polypropylenes.

Acrylic S fibers can be produced by the well-known dry heat stretching process (for example, turbostaple) or wet heat stretching process. Or, the fibers produced by changing the polymer composition of the fibers without the stretching process or by any other well-known processes are also available as long as the shrinkage thereof is included in the range specified according to the present invention.

Next, the shrinkage ac and the latent crimping rate vc of acrylic conjugated fibers C according to the present invention are required to be in the limited range that vc8% and 10%v35%. Although the bulkiness is increased with increasing ac above 0%, it is unfavorable to increase oc above 8%, because the feeling of fullness in the bulkiness is lost by the increase of bulkiness. Further, if vC is less than 10%, three-dimensional crimps forming the intermediate layer portion of bulky yarns according to the present invention are unpreferably weakened, the characteristic compression elasticity and tensile strength are poor, and the touch is degraded. Or, if vc is more than the fibers get strongly entangled and thereby look to decrease bulkiness, so that the whole touch of the products unpreferably loses softness and becomes rough and hard.

Suitable cross-sectional shape of C fibers may be of any type such as bi-metal type |binding, sheath-core type, or their mixed type lbinding of the two or more cornponents, as long as af; and C are included in the said ranges. Further, although the binding structure may preferably be of continuous or regular binding of the components along the fibrous axis in general, the fibers having the structure of intermittent, discontinuous or irregular binding of two or more components along the fibrous axis may also be available for the present invention according to circumstances, as long as ac and C are ineluded in the said ranges.

As the average composition, C fibers are required to contain more than about weight percent of acrylonitrile component. If the acrylonitrile component is less than about 50%, favorable touch tends to be lost. It is desirable to contain more than about Weight percent of acrylonitrile component from the viewpoint of touch and thermal behavior.

In the two or more mutually binded components of C fibers, it is desirable that a difference between the maximum and the minimum of longitudinal thermal shrinkage of fibers prepared by single spinning of each component is more than about 1%. If it is less than about 1%, ac and 11C are not included in the said ranges in many cases.

The conjugated -fibers wherein ac and uc are included in the said ranges are effectively available in the present invention without any relation to the composition thereof. The present inventors have found that, in the case `the conjugated fibers having the composition of a special range are used, the stability of bulkiness in the obtained bulky yarns is very high.

Although any bulky yarns according to the present invention are superior in shape stability to the conventional bulky yarns as described above, it has been found in the further detailed investigations that, in the case the product according to the present invention is repeatedly subjected to such treatment as Wearing, washing and the like, the stabilities of shape and size are sufficiently maintained but the stabilities of bulkiness and fullness are not necessarily sufficient, though they are superior to those of the conventional bulky yarns. That is, in many cases, as the decrease o-f bulkiness and fullness due to these repeated treatments is observed, so the quality of the -product is generally lowered. Then, it has been yfound that this above tendency is most closely related to the kind of the conjugated fibers mainly constituting the intermediate layer according to the present invention. It has further been found that the stability of bulkiness is incomparatively high in the special use of conjugated fibers, wherein at least one kind of the binding components constituting the conjugated fibers is a ternary to multi-components acrylic polymer containing at least more than 80 Weight percent of acrylonitrile component, 4.5 weight percent to 12 'weight percent of acryl amide component, 0.1 weight percent to 2 weight percent of methallyl sulfonic acid component or sulfoalcohol ester component of acrylic acid or methacrylic acid and 0 to 15.4 weight percent of one or more kinds of other ethylene unsaturated cornpound component-s, and further the average possessory ratio of said components is between 30 weight percent and 80 weight percent in the cross-section of the conjugated -ibers. Probably, because such conjugated fibers C as the above have the excellent reproducibility of crimps and the most appropriate shape of crimps, C yfibers get adequately entangled with N fibers and thereby are recovered strains which are produced during wearing, washing and the like. y

In said sulfoalcohol acrylic acid or methacrylic acid ester components, sulfonic acid rnay suitably be not only in the form of free acid but also in the form of such salts as alkali metallic salts, ammonium salts, organic basic salts and the like. In this case, however, the content calculated in terms of free acid form is required to be included inthe said range.

Suitable sulfoalcohols are sulfoethanol, sulfopropanol, sulfobutanol and the like.

As the process for preparing the conjugated fibers suitable for the present invention, there can be employed all the well-known conventional processes, such as Japanese patent publication Nos. 4811/53, 667/59, 2716/60, 1921'4/ 6l, 57218/62, 10860/62 and 1024/63 and U.S. Patent Nos. 2,439,813-2,439,815 and 3,03 8,236-3,038,240.

In case mixed yarn spun or twisted filaments are prepared from non-shrinkable fibers N, shrinkable fibers S and conjugated fibers C, it is necessary that the mixing ratios (weight percent) of fibers N, S and C are included in the range specified by,

N+s+oz1o0 (1) soslo (4) In case N is less than 15%, the yarns become hard to the touch and lack the luster due to the shortage of the density of N fibers inthe surface of the yarns. In case C is less than 25%, the stiffness of knees and elasticity are decreased and the fullness is lost due to the lack of the density of conjugated fibers in the intermediate layer of the yarns, and thereby the yarns come to look thin. In case S is less than 10%, the core portion of bulky yarns become poor and, in general, the shape stability is degradated, and thereby the bulkiness is lacked where N is large while the yarns become rough and hard where N is small. In case S is more than 50%, the core portion becomes so strong that feeling of fullness is unfavorably degradated.

The bulky yarns according to the present invention consist substantially of more than 3 kinds of fibers belonging to 3 groups, N, S and C, but may be added with special fibers belonging to none of N, S and C or other materials as long as the effect of the present invention is injured.

Suitable processes for mixed yarn spinning of N, S and C fibers are 'a process for spinning after mixing their cut fibers with each other, a process for mixed yarn spinning in the form -of sliver and other well-known processes for mixed yarn spinning. Accor-ding to circumstances, dyed cut fibers, shrinkable fibers subjected to the stretch treatment after being dyed, and the like are employable. For mixed yarn twisting, any of the well-known conventional processes for :mixed yarn twisting are similarly available.

The spun yarns `thus obtained according to the present invention are subjected to the hot water treatment, steam treatment, drying treatment and the like during the processes of dyeing, bleaching, finishing and the like, S and N fibers intervening mutually in each other produce each shrinkage, three dimensional orimps are produced or the peculiar yarn structure of bending fibers is formed, to obtain the excellent properties satisfying the objects of the present invention.

From the spun yarns `according to the present invention, various useful fibrous products are obtained by the well-known processes, such as knitting, weaving, dyeing, finishing, adjustment and the like.

The following examples are given below for further detailed explanations ofthe present invention, without any purpose of limiting the scope of the invention.

EXAMPLES OF THE INVENTION Example 1 (1) Sodium hydroxymonosulfonate and sodium hydrogen sulfite were employed as the starting .agent of polymerization, to obtain 2 kinds of polymers a and b having the following compositions.

(2) The said polymers a and b were separately dissolved by the concentration of 15% at -10 C, in 70% nitric acid from which nitrous acid had been removed as much as possible. The obtained dopes were extruded out at the same time from the same nozzle of a special spinneret for conjugated fibers, were coagulated in an aque ous solution of about 30% nitric acid, Were washed with Water, to fully remove the residual nitric acid, and were stretched to 7 times in hot water. After being dried, the filaments were passed through hot water at C. and were subjected to the -oil treatment, drying, and then the steam treatment for checking of shrinkage. Further, by providing mechanical crimps, the tows were obtained, and were cut -so that the average length of fiber might be 102 mm., to obtain the conjugated fibers of 3 d. in single filament denier. Then, the obtained fibers were subjected to carding and then the worsted spinning machine, to obtain the top of the fibers. The average shrinkage as and the average latent crimping rate vs of the conjugated fibers were respectively and 25% (3) Said polymer a was subjected to the same nitric acid type Wet spinning as in Section (2) except that a common spinning nozzle was used. It was then dipped in the oil agent was dried and, after being subjected to the steam treatment, was stretched to 1.39 times through the hot plates at 140 C. and mechanically crimped, to obtain the tows (after shrinking, 3 d. in single filament denier) of fibers (S2) of thermal shrinkage. The tows were cut so that the average length of liber might be 102 mm. and were subjected to the card and the worsted spinning machine, to obtain the top, in the same manner as in (2). The shrinkage as of shrinkable fibers thus obtained was 24%.

(4) The top of common acrylic fibers (3 d., 102 mm. long) (N1) (an:0.5%, 11:0), the top of the conjugated fibers (C1) as described in (2) and the top of the shrinkable (S1) as described in (3) (65:24, 115:0) were subjected to spinning in various ratio thereof and dyeing to cream color by the rotary back type hank dyeing machine and, being applied with the oil agent, were dried. Various dyed yarns of 2/ 32 Nrn. folded yarn thus obtained were knitted to each full fashioned sweater. After being finished and ad- Cil TABLE 3 Coiijugated fiber rc v., Slirinkable fiber .1,

N o. No.

Next, fibers prepared by carrying out the nitric acid type wet spinning of an individual polymer consisting of 90.0% of acrylonitrile, 9.5% of methyl acrylate and 0.5% of sodium methallyl sulfonate were treated with saturated steam at 140 C. and stretched to 1.50, 1.40, 1.30, 1.20 and 1.10 times in hot water at 100 C. By mechanical crimping, drying and cutting of the fibers, 5 kinds of shrinkable fibers of different shrinkage, S21, S22, S23, S21 and S25, were prepared. Each as was shown in Table 3.

The combinations as shown in Table 4 of C12-C25, S21-S25 and N1 prepared in Example 1 were subjected in the ratio of C/S/N:50%/20%/30% (weight ratio) in every case to spinning. After being subjected to dyeing by rotary back type hank dyeing machine as in Example 1, the yarns were knitted to full fashioned sweaters, which were then finished.

The properties and estimate of the finished products were as shown in Table 4.

TABLE 4 Mixing ratio o Properties spinning C S N a b e d e f g h Control.. S22 N i A A A O A Present invention Sie Ni O O Do S22 Ni Do... S22 Ni C) O Control C25 S22 Ni O A A A A Present invention C22 S21 N1 O O A (o) Do C22 S22 Ni O (D) Do C22 S23 Ni D C22 S24 Ni O O (D O Control C22 S25 N1 A A A O A Norm-The signs of properties are as shown in Table 2.

justed, the properties of the obtained sweater were examined and estimated from various points of view. The results were as shown in Table 2. As compared with the group of control products, the superiority of the products according to the present invention is clearly recognized.

From the results in Table 4, the excellent effects of the present invention are clearly understood. Further, it may clearly be recognized that the products prepared under such conditions as do not satisfy the ranges of a'c and vs, especially the range of vc, of C fibers and the range of TABLE 2 Mixing ratio Properties Experiment No. of spinning C S N a b c d e i g li Control group:

5o 50 X X O X 0 X O X O O 0 0 X X X A O 0 75 O O O A O O O O o 50 A A A A 0 25 X A X A 20 20 O O O 2o 3o O O (cg g 2o 4o 2o 5o O O 40 25 O O O O No'rE.-In Table 2, as for the properties, (a) represents .surface smoothness, (b) Ilexibility, (c) luster, (d) compression elasticity, (e) shape stability, (t) stiffness, (g) bulkiiiess and (li) fullness. As for the estimate, X represents no good, A fair, O good and excellent.

Example 2 irs of S fibers limited according to the present invention are distinctly inferior to those according to the present invention.

Example 3 The following 4 kinds of conjugated fibers were prepared in the same manner as in Example 1.

TABLE 5 Composition L Component 1:

Acrylonitrile 89.55 88.55 91.0 90.4 Methyl acrylate.. 4. 0. 0 Vinyl acetate 11. 0 Acrylic amide... 6.0 8.4 Sodium methallyl sulf ate 0. 45 0. 45 0. 6 0. 6 Component 2:

Acrylonitrile 91.5 91.0 96.2 96.2 Methyl acrylate 8.0 3. 3.0 Vinyl acetate 8.5 Sodium methallyl sufonate 0. 5 0. 5 0.8 0.8 Properties:

en 5 4 2 3 v 30 30 16 17.

In the same manner as in Example 1, high, shrinkable acrylic fibers (S2) (as-22, 115:0) and common acrylic fibers (3 d., 102 mm. long) (N1) (rn=0.5, :fn-0), those being marketed were mixed with each of the fibers (L, M, N and P) and then subjected to spinning and extruded to l/48 Nm. single yarns (after being bulked). Separately, bulky yarns consisting of S2 and N1 only were extruded and used as the control in the following tests.

These spun yarns were bank-dyed with rotary back dyeing machine and applied the oil agent, and then knitted to double piqu jersey, which was then subjected to the finish treatment. The properties thereof for 9 items were examined and estimated. The results are as shown in Table 6. 4 kinds of jersey according to the present invensuperior to the conventional ones. Further, even in the range according to the present invention, it is obvious that the conjugated fibers having the composition included in range (L and .N) specified in claim 3 are especially superior.

TABLE 7 Experiment N o.

Retention rate of bulkiness (percent) Present invention L 91 M 78 N 87 P 72 Control Q 55 tion were all excellent.

TABLE 6 Mixing ratio of Properties Experiment spinning C S N a b c d e t' g h 4o 25 35 4o 25 35 O 23 a sssssssee o 5o 5o A O X A X NOTE.-As for the properties, (a) represents the smoothness of surface touch, (b) softness of surface touch, (c) luster, (d) compression elasticity (repulsive force), (e) shape stability, (f) stiffness, (g) lbulkinessthickness and (h) feelingof fullness.-

As for the estimate, X represents no good, A fair, O good and excellent.

Then, the comparative test on the stability of bulkiness of these jersies was made. In the test, `l() sheets of 10 cm. x 10 cm. test piece were piled up so that course and wale might be arranged alternately. The procedure of leaving under compression and washing-drying was rcpeated l0 times, and the retention rate -of bulkiness before and after each repetition were obtained, wherein Bulkiness (percent) Thickness under loading of Z g./clm.2-

Thickness under loading of 150 g./e m.2

Thickness under loading of 150 g./cm.2 v X 100 Retention rate of bulkiness (percent)= Bulkiness after treatment X 100 Bulkiness before treatment The test conditions are as follows:

Compression conditions-Pressure 50 g./cm.2, temperature 25 C., humidity 65% RH. Leaving time for each time, 20 hrs.

Washing conditions- The test piece was washed in 0.2% aqueous solution of nonionic detergent in 40 C., for 15 min., with an electric washing mach-ine, after central dehydration, drying under sun light outdoors.

The results were shown in Table 7. As for the reduction of thickness, that is, stability of bulkiness, the bulky yarns according to the present invention were distinctly and the composition ratio (weight percent) of N, S and C is in the ranges limited by Equations l to 4,

2. Mixed spun or twisted yarns, according to claim 1, wherein said shrinkable fibers S consist of a single component containing at least more than 50 weight percent of acrylonitrile component.

3. Mixed spun or twisted yarns, according to claim 1, wherein, amon-g at least 2 kinds of eccentrically bound components in the cross-section of said conjugated fibers, at least one kind of component is a ternary or more multiple component acrylic polymer containing more than weight percent of acrylonitrile component, 4.5 weight percent to l2 weight percent of acryl amide, 0.1 weight percent to 2 weight percent of methallyl sulfonic acid component or sulfoalcohol acrylic or methacrylic acid ester component and further 0 to 15.4 weight percent of one or more kinds of ethylene unsaturated compounds other than these components, and the average possessory rate of said components is between 30 weight percent and 80 weight percent in the cross-section of the conjugated fibers.

4. Mixed spun or twisted yarns, characterized in that the yarns consist of non-shrinkable fibers N consisting of a single component containing at least more than 50 weight percent of acrylonitrile component, shrinkable fibers S, and conjugated fibers C containing at least more than 50 `weight percent of acrylonitrile in the average composition and having the cross-sectional structure wherein 2 or more different components are eccentrically bound, the shrinkage o' and the latent crimping rate v defined in the detailed explanation of said 3 kinds of the components are in the ranges of,

For C, ogcgs, 10Vc35 5 and the composition ratio (weight percent) of N, S and C is in the ranges limited by Equations 1 to 4,

N+S+C-100 (1) N215 2) i0 C225 (3) said slirinkable bers are mainly positioned in the state of central ,portionyand the non-shrinkable fibers mainly surround theconjugated fibers thereby forming the fibrous surface.

Tieferences Citedl UNITED STATES PATENTS Evans 57-140 Earnshaw 57-140 Kitson et al 57-140 Humphreys 57-140 Maerov et al 57-140 Lulay et al. 57-140 Fujita et al. 28-72 XR being relatively stretched in the central portion of the 15 JOHN PETRAKES, primary Exame,.

bulky yarns, said conjugated bers mainly surround the 

